Although chronic kidney disease (CKD) is the precursor to end-stage renal disease (ESRD), few studies of outcomes after ESRD have captured information about events that occurred during CKD. Basic and important questions therefore remain unanswered. For example, how do interventions during the CKD phase of disease affect outcomes at the ESRD phase of disease? The major goal in this study is to understand whether and how mortality risk among ESRD patients is affected by tightness of blood pressure control during CKD. To achieve this, we will study enrollees of two completed NIH-sponsored randomized controlled trials: the Modification of Diet in Renal Disease (MDRD) study and the African American Study of Kidney Disease and Hypertension (AASK). Both MDRD and AASK enrolled patients during the CKD phase of disease, but numerous participants went on to develop ESRD and their post- ESRD outcomes can be tracked via United States Renal Disease System (USRDS), the nationally comprehensive ESRD registry. Our research approach and study design lends opportunities to examine how other therapeutic choices during the CKD phase of disease will affect outcomes after ESRD. By linking USRDS with MDRD and AASK, we will gain new insight into modifiable risk factors contributing to the high rates of adverse outcomes among patients with ESRD. Our results may inform the debate about how tightly blood pressure should be managed among CKD patients as well as guide nutrition management and other aspects of care in kidney disease patients.